Devices and methods for treating a nerve of the nasal cavity using image guidance

ABSTRACT

The invention disclosed here generally relates to devices used to identify the location of a never in order to modify a property of the nerve. Specifically, the invention utilized pre-operative scans of a patient&#39;s nasal cavity in order to identify target treatment locations when a nerve to be treated is located. The image of the nasal cavity and target treatment location can be registered with the real time position of the nasal cavity using a surgical navigation system in order to assist in guiding a surgical probe to the target treatment location.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional PatentAppln. Ser. No. 62/364,753 filed Jul. 20, 2016, entitled “Image GuidedSurgical Procedures”, the full disclosure of which is incorporatedherein by reference in its entirety for all purposes.

BACKGROUND OF THE INVENTION

The nose includes the external nose on the face and the nasal cavity,which extends posteriorly from it. The nose functions in smell andprovides filtered, warm, moist air for inspiration. The external nosepresents a root (or bridge), a dorsum, and a free tip or apex. The twoinferior openings are the nostrils (or nares), bounded laterally by theala and medially by the nasal septum. The superior part of the nose issupported by the nasal, frontal, and maxillary bones; the inferior partincludes several cartilages. The continuous free margin of the nasalbones and maxillae in a dried skull is termed the piriform aperture. Thenasal cavity extends in an antero-posterior direction from the nostrilsto the choanae. The choanae are the posterior apertures of the nose.Each choana is bounded medially by the vomer, inferiorly by thehorizontal plate of the palatine bone, laterally by the medial pterygoidplate, and superiorly by the body of the sphenoid bone. Posteriorly, thenasal cavity communicates with the nasopharynx, which in many respectsmay be regarded as the posterior portion of the cavity. The nasal cavityis related to the anterior and middle cranial fossae, orbit, andparanasal sinuses and is separated from the oral cavity by the hardpalate. In addition to the nostrils and choanae, the nasal cavitypresents openings for the paranasal sinuses and the nasolacrimal duct.Further openings, covered by mucosa in vivo, are found in a dried skull,e.g., the sphenopalatine foramen. The nasal cavity is divided into rightand left halves, each of which may be termed a nasal cavity, by thenasal septum. Each half has a roof, floor, and medial and lateral walls.The roof of the nasal cavity is formed by nasal cartilages and severalbones, chiefly the nasal and frontal bones, the cribriform plate of theethmoid, and the body of the sphenoid. The floor, wider than the roof,is formed by the palatine process of the maxilla and the horizontalplate of the palatine bone, i.e., by the palate. The medial wall, ornasal septum, is formed (from anterior to posterior) by the septalcartilage, the perpendicular plate of the ethmoid bone, and the vomer.The lateral wall is uneven and complicated and is formed by severalbones: nasal, maxilla, lacrimal and ethmoid, inferior nasal turbinate,perpendicular plate of palatine, and medial pterygoid plate of sphenoid

The lateral wall presents three medial projections termed nasalturbinates, which overlie passages (meatuses). The inferior turbinate isa separate bone; the others are portions of the ethmoid bone. Thesuperior meatus, under cover of the superior turbinate, receives theopenings of the posterior ethmoidal cells and (in a dried skull) thesphenopalatine foramen. The middle meatus, under cover of the middleturbinate, receives the openings of the maxillary and frontal sinuses.Most anterior ethmoidal cells open on an elevation (ethmoidal bulla). Acurved slit (hiatus semilunaris) inferior to the bulla receives theopening of the maxillary sinus. The frontal sinus and some anteriorethmoidal cells open either into an extension (ethmoidal infundibulum)of the hiatus or directly into the anterior part (frontal recess) of themiddle meatus. The inferior meatus, which lies between the inferiorturbinate and the palate, receives the termination of the nasolacrimalduct. The nasal cavity is continuously covered by mucosa. The posteriortwo thirds have active ciliary motion for rapid drainage backward anddownward into the nasopharynx. The nasal mucosa is highly vascular, andit warms and moistens the incoming air. The mucosa contains largevenous-like spaces (“swell bodies”), which may become congested duringallergic reactions or infections. The mucosa's functionality iscontrolled by the nerves that innervate the nasal cavity. The nerves areresponsible for sensations of touch, pressure, temperature, andregulation of blood supply and secretion of the nasal mucosa. Thesenerves include the anterior ethmoid nerve (AEN), the nasopalatine nerve(NPN), the posterior inferior branch of the greater palatine nerve(GPN), and the posterior nasal nerve (PNN). Figure below shows a map ofthe innervation.

The anterior ethmoid nerve is the continuation of the nasociliary nerve.It innervates the nasal cavity at the anterior ethmoidal foramen and thenasal slit. This nerve supply sensory fibers to the mucosa of theethmoidal sinuses, the anterior aspect of the nasal cavity, and the skinon the lateral sides of the nose. The nasopalatine nerve is a branchfrom the sphenopalatine ganglion (SPG), it innervates the nasal cavitythrough the sphenopalatine foramen (SPF), once in the nasal cavity itpasses along the roof of the nose and into the nasal septum and coursesits way down the nasal septum, and through the incisive foramen tosupply the mucous membrane of the hard palate. At the ganglion, itreceives parasympathetic fibers which supply the nasal and palatinemucosal glands as well as special sensory fibers (taste). The posteriorinferior branch of the greater palatine nerve branches off the greaterpalatine nerve in the greater palatine canal and exits the canal througha tiny un-named foramen in the palatine bone to enter the nasal cavity.In the lateral wall of the nasal cavity it supplies the posteriorinferior mucosa including the inferior concha and middle and inferiormeatus. At the sphenopalatine ganglion, it also receives parasympatheticfibers which are carried by the greater palatine nerve before itbranches off that supply nasal glands. The posterior nasal nerve alsobranches from the ganglion and enters the nasal cavity through the SPF.At the ganglion, it receives parasympathetic fibers which supply nasalglands. It leaves the fossa inferomedially through the sphenopalatineforamen with the nasopalatine nerve to enter the posterosuperior nasalcavity just behind the superior nasal meatus where it divides into themedial and lateral branch. Medial branches supply the posterosuperiorquadrant of the nasal septum and the lateral branches supply theposterosuperior quadrant of the lateral nasal wall.

FIGS. 1A-1E illustrate various views of the nasal cavity includingshowing the anatomical features noted above.

Disorders involving these nerves have been linked to rhinitis symptomsincluding runny nose, nasal congestion, sneezing, and itching, as wellas, chronic pain, cluster headaches, and migraines. Various treatmentsincluding physically damaging (comprising, cutting, or removing),thermal ablating, or chemically altering of these nerves have shown toprovide relief to patients that suffer from the above ailments. Anexample of therapies targeting nasal nerves to address these ailmentsare described in U.S. patent application Ser. No. 15/242,362 filed Aug.19, 2016, entitled “APPARATUS AND METHODS FOR TREATING RHINITIS”, whichis incorporated herein by reference in its entirety for all purposes.

A challenge in treating the symptoms of rhinitis is accurately targetingthe desired nerve as well as the branches of the nerve as the nervefibers branch throughout the nasal mucosa and are not visible on thesurface of the mucosa, for example using an endoscope. One methodphysicians use in an attempts to identify the nerves is by making anincision in the mucosa, and pulling the mucosa away from the bone. Thismethod has the disadvantage of requiring general anesthesia and furtherthe procedure is invasive and requires a lengthy recovery time. Anothermethod physicians use to attempt to identify the nerves is byidentifying visible landmarks using a rigid endoscope and define thetreatment area to treat around the areas where the nerve fibers arepredicted to be based on the visible landmarks. This approach has thedisadvantages of being imprecise. In some cases, this method proves tobe challenging because a large percentage of the patients having theprocedure performed previously have underwent other procedures that havealtered these surface visual anatomical landmarks that are used toidentify innervation and/or these patient's mucosa is inflamed making itchallenging to advance an endoscope into the nasal cavity to visualizelandmarks when present.

Therefore there exists a need for identifying the location of nerveswithin the nasal cavity that is not invasive and is precise even in thepatients with altered surface visual landmarks or inflamed mucosa.

BRIEF SUMMARY OF THE INVENTION

The present technology utilizes image-guided surgery (IGS) to assist aphysician with identifying nerves to be targeted in the treatment ofrhinitis and other conditions.

Embodiments of the present technology address the need for identifyingthe location of nerves noted above by providing a nerve treatmentinstrument with one or more location sensors that are trackable with asurgical navigation system. Target treatment areas may be identifiedpre-operatively using scan of the nasal cavity that are used by thesurgical navigation system during the procedure to assist the physicianwith navigating a surgical probe using real-time 3-D imaging feedback oflocation to multiple anatomical landmarks. With the technology disclosedherein, physicians are able to pinpoint anatomical landmarks andlocation of their instruments in the nasal cavity with minimal directvisualization and are able to identify landmarks even if the surface hasbeen altered by a previous surgery. This enables the physicians to moreconfidentially identify potential locations of the nerves to be treatedwithout cutting the mucosa.

Further aspects, details and embodiments of the present invention willbe understood by those of skill in the art upon reading the followingdetailed description of the invention and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIGS. 1A-1E shows various view of nasal cavity anatomy.

FIGS. 2A-2D show an embodiment of a surgical device with a removablelocation sensor.

FIGS. 3A-3F show embodiments of an end effector.

FIGS. 4A-4G show embodiments of a surgical device with imbedded locationsensors.

FIGS. 5A-5C show an embodiment of an alignment process.

FIGS. 6A-6D show an embodiment of a radio ablation catheter withimbedded location sensors.

FIG. 7 shows an embodiment of a system including a surgical navigationsystem and a surgical device.

FIG. 8 shows a flowchart of an embodiment of a method for performing anablation procedure.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally relates to medical devices, systems andmethods, and more particularly relates to devices, systems and methodsthat treat rhinitis. Such treatment of rhinitis is achieved bydecreasing or interrupting nerve signals that are transmitted from thesphenopalatine ganglion to the nasal mucosa via the posterior nasalnerves. A decrease or interruption of nerve signals can be attained by avariety of methods, particularly by the application of physicaltherapies (compression or cutting), thermal therapies (heat or cold), orchemical therapies (alcohol or anesthetic injections). Examples ofthermal therapies include cryotherapy, cryoneuromodulation,cryomodulation, cryolysis, cryoablation, and thermoablation. It has beenfound that a specific target area within the nasal cavity isparticularly effective in treating rhinitis.

The present technology may include a surgical navigation device which isused for Image guided surgery (IGS) procedures. The surgical navigationdevice may include a computer work station, a video monitor, a localizerand a sensor tracking system. The sensor tracking system is configuredto track the location of one or more location sensors that be may beattached to surgical instruments. The location sensors mounted on thesurgical instruments and the corresponding tracking system may beoptical, electromagnetic or electromechanical.

Prior to an ablation procedure being performed, a patient may have adigital tomographic scan performed of their nasal cavity. The digitaltomographic scan may be converted into a digital map which can be viewedon a computer with one or more two-dimensional views, and/or athree-dimensional view of the nasal cavity. The digital map may also bereferred to as an image of the nasal cavity. As will be discussed below,the image of the nasal cavity may be used to identify target treatmentlocations within the nasal cavity.

In order to utilize the pre-operative image of the nasal cavity duringan ablation procedure the image is registered to the position of thepatient and the surgical tools in a common reference frame. Inembodiments, a localizer is used to register the preoperativetomographic image data with the real time physical position of thepatient's body, particularly the patient's nasal cavity, during theablation procedures described herein. The sensor tracking system servesto track the position of each location sensor-equipped surgicalinstrument during the surgery and to communicate such information to thecomputer workstation. Registration is the process of matching two setsof data and in this case matching the image of the nasal cavity from thepreoperative tomographic scan to intraoperative patient body positiondata so that the image displayed on the monitor of the surgicalnavigation device will show the positions of location sensors onsurgical instruments relative to the locations of anatomical structuresshown on the tomographic image in order to determine the position of thesurgical instrument in the nasal cavity. In embodiments, one of a numberof different registration strategies may be used including intrinsicstrategies and as extrinsic strategies.

For example, in embodiments, registration is performed as an intrinsicregistration strategy known as anatomical fiducial registration. Withanatomical fiducial registration, a number of fiducial markers areplaced at specific anatomical locations on the patient's body during thepreoperative tomographic scan and during the surgical procedure. Thesefiducial markers are typically positioned on the patient's head or faceat locations that correspond to specific anatomical landmarks within theears, nose and/or throat. The fiducial markers may be mounted on a headset or frame that is worn by the patient or the fiducial markers may beaffixed directly to the patient's body (e.g., by adhesive attachment tothe skin, anchoring into bone, etc.). In embodiments other registrationstrategies may be used to register the image of the nasal cavity toposition of the patient's nasal cavity in a reference frame.

Once a registration process is completed, the ablation procedure may beperformed. In embodiments, to correlate head position with the trackingsystem, the fiducial markers remain in fixed position on or in thepatient's body until after the ablation procedure has been completed.Unlike some procedures, for example neurosurgical procedures, thatrequire the patient's head to be fixed in a rigid stereotactic frame, inembodiments that use fiducial markers mounted on or in the patient'sbody may allow for free movement and repositioning of the patient's headduring the procedure, and the registration process may be continuallyperformed so that the actual position of the patient's nasal cavity iscorrelated in the reference frame with the image of the nasal cavity.

The computer workstation of the surgical navigation device is configuredto display one or more image(s) on a monitor showing the image of thenasal cavity along with an indication, such as a cross hairs or arepresentation of the surgical instrument, of the real time position ofthe surgical instrument within the nasal cavity. The image of the nasalcavity may be displayed as any combination of two-dimensional planeviews (e.g. sagittal plane, coronal plane, transverse plane), and threedimensional views. In this manner, a physician is able to view theprecise position of each sensor-equipped instrument relative to thesurrounding anatomical structures shown on the tomographic scan.

In embodiments the surgical navigation may include electromagneticsensors/tracking systems where radiofrequency electromagnetic locationsensors (e.g., electromagnetic coils) are placed on the surgical deviceand on a localizer frame worn by the patient. A transmitter ispositioned near the operative field. The transmitter transmits signalsthat are received by the surgical instrument-mounted sensors andlocalize mounted sensors. The tracking system detects variations in theelectromagnetic field caused by the movement of the instrument-mountedsensors relative to the transmitter. Examples of electromagneticsurgical navigation systems that may be used with the present technologyinclude the Fusion ENT Navigation system available from MedtronicNavigation, Louiville, Colo., Fiagon Navigation System from Fiagon GmbHHennigsdorf, Germany, the KICK EM from Brainlab, Inc., Westchester, Ill.

In embodiments, the surgical navigation system includes anelectromechanical sensors/tracking systems that includes a multi-jointedarticulating mechanical arm attached to the surgical instrument. Themulti-jointed articulating mechanical arm includes sensors to measuremovements of the joints that are used to determine the location of theinstrument based on signals received from the sensors.

In embodiments, the surgical navigation system includes opticalsensors/tracking systems that detect/track optical navigation elements(e.g., infrared light emitting LEDs or passive markers) that are placedon the surgical instruments and detects/tracks a localizer frame worn bythe patient. Camera(s) is/are positioned to receive light emitted orreflected from the navigation elements. Examples of optical trackingsystem that may be used with the technology herein is the LandmarXEvolution® ENT II Image Guidance System available from Medtronic XomedSurgical Products, Inc., Jacksonville, Fla.; VectorVision® system andKolibri® system available from BrainLAB, Inc., Westchester, Ill.

The surgical navigation system may be used to track a surgical device,such as a surgical probe used for ablation of a tissue region within thenasal cavity. The surgical probe may have one or more location sensorsthat are trackable by the surgical navigation system. In embodiments,the location sensor may be built into the surgical device at the time ofmanufacture or may be attached immediately prior to or during use of thesurgical device for the ablation procedure. In embodiments, one or morelocation sensors may be attached or integrated into any of the devicesdescribed in patent application publication number US 2015/0164571 A1,which is incorporated by reference herein.

FIGS. 2A-2D show an embodiment of a surgical probe device 200. Thesurgical probe device includes a handle 202, an energy source (notshown) within the handle, a probe 204 shaft extending from the handle,an ablation end effector 206 in communication with the energy source,and an energy activation switch 208. In embodiments, for example asshown in FIG. 2A, a location sensor 210 is attached to a portion of thehandle. As noted above, during an ablation procedure, location sensorsor markers mounted on the surgical device communicate with or aredetected by the surgical navigation system in order to indicate theposition of each location sensor in order to determine the position andorientation of the surgical device, and in embodiments the position andorientation of the end effector. The surgical navigation systemcorrelates the data or signal received from the location sensors withthe reference frame of the image of the nasal cavity and the actualposition of the nasal cavity.

FIGS. 3A-F show embodiments of ablation end effectors that may be usedwith the technology disclosed herein. FIG. 3A is a schematicillustration of a side view of and embodiment of a distal end of asurgical probe 79 comprising expandable membranous structure 80encompassing spring-like structure 82. Spring-like structure 82 isconfigured as a loop structure as depicted. Expandable membranousstructure 80 is depicted in its un-expanded state. FIG. 3B is aschematic illustration of the same side view in FIG. 3A of surgicalprobe 79 with its expandable membranous structure 80 in its expandablestate. FIG. 3C is a schematic side view illustration taken at view C-Cfrom FIG. 63. FIG. 63 is a schematic side view illustration taken atview D-D from FIG. 3B. Surgical probe 79 is configured with expandablemembranous structure 80 functioning as a liquid cryogen evaporationchamber. Liquid cryogen enters the interior of expandable membranousstructure 80 from encompassed spring-like structure 82. Evaporatedcryogen gas exits the interior of expandable membranous structure 69through fenestration(s) in distal end 146 of probe shaft 145 and exitssurgical probe 79 proximally into the room. Spring-like structure 82 isconfigured to pre-tension expandable membranous structure 80 in oneradial axis to a greater extent than a second radial axis in a mannerthat causes expansion to be constrained in the radial axis with greatestpre-tensioning. In FIGS. 3A and 3B, spring-like structure 82 isconfigured to pre-tension membranous structure 80 to a greater extent inthe radial axis that is normal to the view axis. In FIGS. 3C and 3D,spring-like structure 82 is configured to pre-tension expandablemembranous structure 80 to a greater extent in the radial axis that isparallel to the view axis. FIG. 3A and FIG. 3C depict surgical probe 79with expandable membranous structure 80 in its un-expanded state. FIGS.3B and 3D depict surgical probe 79 with expandable membranous structure80 in its expanded state. Pre-tensioning of expandable membranousstructure 80 provides a means for achieving a predetermined expandedshape for optimal matching of the morphology of the target area of thelateral nasal wall.

FIG. 3E shows a side view of an embodiment including a structure ormember 83 which is formed into a looped and elongated structure havingarcuate edges for presenting an atraumatic surface. Rather than beingformed as a spring like structure, the structure 83 may be formed of arelatively rigid wire or member instead which maintains itsconfiguration when pressed against a tissue surface. Structure 83 mayform a continuous structure which defines an opening there through suchas a looped or elongated and looped member which is open through theloop. The structure 83 may be contained entirely within the expandablestructure 81 which may be formed to have a predefined shape which isdistensible or non-distensible when inflated by the cryogen. Moreover,the expandable structure 81 may be formed to surround the structure 83entirely without being supported by or attached to the structure 83itself. Such a structure 83 may provide a configuration which presents alow-profile as the device is advanced into and through the nasal cavityand between the nasal turbinate tissues. Yet because of the relativelyflattened shape and rigidity and integrity of the structure 83, thestructure 83 may be used to manipulate, move, or otherwise part thetissues of the nasal cavity without having to rely upon the expandablestructure 81. Additionally, the low-profile enables the structure 83 tobe positioned desirably within the narrowed confines of, e.g., thecul-de-sac in proximity to the posterior nasal nerves. When theexpandable structure 81 is in its deflated state, it may form aflattened shape and when inflated, the expandable structure 81 mayinflate into a configuration which remains unsupported by or attached tothe structure 83. Because the structure 83 may be formed of a memberwhich solid along its length, the cryogen may be introduced directlyinto the expandable structure 81 through a distal opening defined in theprobe shaft 145.

In embodiments, for example as shown in FIGS. 2A-2D, surgical device 200may include surfaces configured to receive a removable location sensor.For example, as shown in FIGS. 2C and 2D, handle portion includes adetent 212 comprising flat opposing parallel walls that are configuredto receive location sensor 210. The detent 212 is configured to preventmovement of the location sensor 210 relative to the surgical device 200so that the relative locations of other portions of the surgical devicerelative to the location sensor remain constant during the procedure. Asshown, in this configuration the location sensor 210 is positioned onthe most distal end of the handle 202 which is a portion of the devicethat remains outside of the nasal cavity during an ablation procedure.This location has the advantage of ensuring the location sensor remainsin the navigation field, i.e. reference frame, throughout the procedurewithout obstructing direct visualization or additional tool paths. Aswill discussed in greater detail below, after a removable locationsensor is attached to a surgical device, the assembly may be calibratedso that the relative location of the distal end effector is knownrelative to the location sensor. Once the instrument is calibrated withthe sensor, the physician can track the end effector inside the nasalcavity with the surgical navigation system. In embodiments, locationsensors can be attached to the proximal end of the cannula in a similarmanner as a Fiagon adapter.

In embodiments, for example as shown in FIGS. 4A-4G, location sensors410 may be integrated internally in the surgical device 400. Forexample, a location sensor 410 may be imbedded into the handle 402 asshown in FIGS. 4A-4C. In embodiments where the location sensor 410 iswired the wiring 414 may extend out of a port 416 in the handle of thesurgical device. The handle may include a bracket to fix the locationsensor and further the location sensor may be attached using standardattachment methods (e.g. epoxy, adhesive). In embodiments with imbeddedlocation sensors, the location sensors may be pre-calibrated to thedistal tip and/or ablation end effector at the time of manufacture orprior to a procedure being performed. Pre-calibration may eliminated theneed to calibrate the position of the location sensor relative to theablation end effector at the time of the procedure. In embodiments, thelocation sensor 410 may be positioned at any location on the surgicaldevice, for example proximate to where the ablation end effectorattaches to the probe shaft, as shown in FIG. 4D. Location sensorslocated on or proximate to the end effector have the advantage ofallowing the position of the end effector to be determined moreprecisely particularly in embodiments where the probe shaft or endeffector are malleable or semi-rigid and do not maintain their relativeposition in relation to the handle portion of the surgical device. Inembodiments, the location sensors may be the Aurora 5DOF or Aurora Mini6DOF from NDI, Ontario, Canada.

In embodiments, for example as shown in FIGS. 4E-4G, location sensors410 may be placed on or within an ablation end effector 206 in a planeconfiguration, for example in a circular pattern. The ablation endeffector may include a planar member that the location sensors aredisposed on. In embodiments the plurality of sensors may be in otherconfigurations, for example a line, circle, square, or another uniquegeometry that provides an area in a 2-D plane for treatment. Thelocation of the location sensors of the plane may be displayed by thesurgical navigation system and used to position and orient the surfaceof the end effector onto a target treatment surface of a patient'smucosal surface. As shown in FIG. 5A prior to performing an ablationprocedure, reference points 502 with the same relative geometry to eachother as the location sensors may be established in the reference frameof the image of the nasal cavity. During the procedure representations504 of the location sensors displayed by the surgical navigation system,as shown in FIG. 5B, may be navigated within the nasal cavity to alignwithin a range of the reference points 502, as shown in FIG. 5C, inorder to position the surface of the ablation end effector at thedesired target treatment location. Navigation using a plurality oflocation sensors and reference points provides the advantage ofachieving a precise location and orientation of the end effector.

As discussed above, the end effector may be a cryo-ablation endeffector, however, the target treatment position identification andnavigation technology disclosed herein may also be used with other typesof ablation. For example, as shown in FIGS. 6A-6D, in embodiments asurgical device may include a radiofrequency catheter 600 with aplurality of electrodes 602 disposed near a distal end. The electrodes602 are configured to emit radio frequency energy which penetrate andablate tissue. The catheter 600 can be articulated to form asemicircular structure, as shown in FIG. 6B, or a serpentine structure,as shown in FIGS. 6C and 6D. In embodiments, the catheter 600 mayinclude location sensors 610, as discussed above, proximate to eachelectrode 602. The location sensors are detected by the surgicalnavigation system and the configuration, location, and orientation ofthe articulated distal end can be displayed in the reference frame overthe image of the nasal cavity during an ablation procedure.

In embodiments, a system, as shown for example in FIG. 7, including asurgical navigation system 701 and a surgical device 700, as discussedabove, may be used during the performance of identifying and treating anerve within the nasal cavity of a patient. As shown in FIG. 8, anembodiment of a method includes generating an image of the nasal cavity802, identifying a target treatment location 804, registering the imageof the nasal cavity with the position of the nasal cavity and thesurgical device 806, navigating the surgical device to the targettreatment location using the surgical navigation system 808, andperforming ablation at the target treatment location 808.

A discussed above, an image of the nasal cavity may be generated from apreoperative scan of the patient's nasal cavity. The image of the nasalcavity may be analyzed by a physician and/or image recognition softwareto determine a target treatment location in order to ablate a desirednerve. The target treatment location may be determined by identifyinganatomical landmarks in the image of the nasal cavity and usingpredetermined relations of nerves locations relative to the anatomicallandmarks. In embodiments, the anatomical landmarks are not identifiablevisually with an imaging device within the nasal cavity. For example,the landmarks are covered by mucosa and can only be identified throughscans (e.g. CT, X-ray, or MRI scans) that enable seeing under the mucosasurface without physically cutting and removing the surface.

The anatomical landmark may be one or more of the sphenopalatineforamen, the ethmoid crest, the inferior turbinate bony ridge, theintersection of a posterior fontanelle and a perpendicular plate of apalatine bone, the anterior nasal spine, the most posterior attachmentpoint of the middle turbinate to the lateral wall, and the piriformaperture. The landmarks may be used to determine the location ofinnervation and the nerve trajectory in order to determine a targettreatment location to ablate the nerve at the determined location.

In embodiments, the target treatment location may be determined based onone or more of size of the landmark, location of the landmark, distanceand direction to another other landmark, and stored relations betweenanatomical structures and nerves. The determined target treatmentlocation may be visually displayed to a physician overlaid on the imageof the nasal cavity in order to assist the physician in positioning asurgical device at the target treatment location during the ablationprocedure.

In embodiments, the target treatment location may be defined by aplurality of reference points. As noted above, the relative geometry ofthe reference points may correspond to the relative geometry of aplurality of location sensors on an end effector of a surgical device.For example, three reference points may be defined including a firstreference point corresponding to an intersection of a posteriorfontanelle and a perpendicular plate of a palatine bone, a secondreference point corresponding to the sphenopalatine foramen: and a thirdreference point corresponding to a ridge of an inferior turbinate.

The target treatment position may be stored as a visual overly on theimage of the nasal cavity. The visual overlay may include an indicationof the location of the target treatment area. For example the targettreatment area may be a point in the image of the nasal cavity or storedas a surface having a different color than the surrounding surface inthe image of the nasal cavity. In embodiments, the target treatmentlocation may be determined during the ablation procedure withoutpre-identifying the target treatment position.

In embodiments, the location sensors of the surgical device arecalibrated to the position of the end effector prior to performing theablation procedure in order to ensure that the surgical navigationsystem show a precise location of the surgical device in the referenceframe of the image of the nasal cavity. In embodiments, a calibrationtool for use in calibrating the surgical navigation system to a surgicaldevice including location sensors. In embodiments calibration isperformed on surgical devices that has a substantially fixed shapewherein the location sensor is not attached proximate the end effector.The calibration tool may comprise a substantially rigid body having areceiving groove, and a first calibration tip. The calibration tool mayfurther include a second calibration tip. In embodiments, the first andsecond calibration tips extend in 180 degree opposite directions fromone another. The surgical device is insertable into the receiving groovewith its distal end positioned in a known position relative to the firstand second calibration tips. The first and second calibration tips arealternately placeable in a known location relative to an electromagnetictransmitter such that readings may be taken by the surgical navigationsystem and used to calibrate the surgical navigation system to thedistal portion, particularly the end effector of that medical device.Once calibrated, the end effector is registered in the reference frameand may be displayed with the image of the nasal cavity to show the realtime position of the end effector. As noted above, in embodiments, thelocation sensors of the surgical device may be pre-calibrated.

With the location sensors of the surgical device registered, thesurgical device may be used to perform an ablation procedure at thetarget treatment location. To perform the ablation procedure, thepatient 703 may be positioned on an operating table 705, as shown inFIG. 7, and the nasal cavity may be registered with the pre-operativeimage of the nasal cavity. For example, as discussed above, registrationmay be done with a localizer frame 707 with fiducial markers attached tothe head. However, as discussed above, other registration strategies maybe used based on the type of location sensors used by the surgicalnavigation system.

The surgical navigation system is configured to display a one or moresuperimposed images of an indication of the position of the surgicaldevice over the image of the nasal cavity on a display. The physicianmay use the displayed indication of the surgical device to place the endeffector into the nasal cavity and be positioned at the target treatmentlocation. As noted above, the surgical navigation system may display anindication of the target treatment location over the image of the nasalcavity. In embodiments an imaging device, e.g. an endoscope, within thenasal cavity may be used to assist in navigating the surgical device.The surgical navigation system may display an image from the imagingdevice adjacent to the images of the nasal cavity. Displaying the imageof the nasal cavity has the advantages of allowing a physician toovercome the shortcomings of endoscopic imaging including beingspatially limited, being two dimensional, and only having aline-of-sight view. In embodiment a combination of landmarks visiblewith the imaging device and landmarks visible in the image of the nasalcavity but not the imaging device may be used to determine the targettreatment location.

The physician navigates the surgical device using the indication of theend effector on the display of the surgical navigation system to alignthe end effector with the target treatment location. In embodimentsincluding multiple location sensors in a plane, as shown in FIGS. 4E-4G,and a plurality of reference points defining the target treatmentlocation, the physician may navigate the surgical device using thedisplay of the surgical navigation system to align each location sensorto align with a reference point in order to place a surface of the endeffector against a target treatment surface.

Once the end effector is desirably placed against the target treatmentposition, the therapy may be applied. Such therapy may include heat,such as thermoablation, or cold, such as cryotherapy (cryoablation),radio ablation or chemical ablation. In embodiments, the ablation iscryoablation and cryogen liquid is delivered through a small deliverytube as described in commonly owned U.S. patent application Ser. No.14/503,060 filed Sep. 30, 2014, entitled “APPARATUS AND METHODS FORTREATING RHINITIS”, which as previously noted is incorporated herein byreference in its entirety for all purposes.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby

The invention claimed is:
 1. A method for identifying a tissue regionfor treatment within a nasal cavity of a patient, the method comprising:identifying a target treatment location of the tissue region using animage of the nasal cavity; inserting an ablation end effector of asurgical probe into the nasal cavity; registering the ablation endeffector of the surgical probe in the nasal cavity with the image of thenasal cavity to establish a reference frame; positioning the ablationend effector at the target treatment location based on a position of oneor more location sensors on the surgical probe relative to the referenceframe established by registering the ablation end effector of thesurgical probe with the image of the nasal cavity, wherein positioningthe ablation end effector at the target treatment location comprises:determining the position of one or more location sensors disposed on thesurgical probe with respect to the reference frame, and determining whenthe ablation end effector of the surgical probe in the nasal cavity isaligned with the target treatment location prior to ablation of thetissue region; and performing ablation of the tissue region when theablation end effector is aligned with the target treatment location. 2.The method of claim 1, wherein the image of the nasal cavity is based ona computed tomography scan or a magnetic resonance imaging scan.
 3. Themethod of claim 1, wherein the reference frame is established usinganatomical features of the patient or location sensors attached disposedon the patient.
 4. The method of claim 1, wherein determining the targettreatment location comprises identifying the sphenopalatine foramen inthe image of the nasal cavity.
 5. The method of claim 4, wherein thetarget treatment location is determined measuring a predetermineddistance or a predetermined direction from the sphenopalatine foramen inthe reference frame.
 6. The method of claim 4, wherein the targettreatment location is a surface in the nasal cavity and whereindetermining the target treatment location comprises identifying aplurality of reference points to define the surface.
 7. The method ofclaim 6, wherein the reference points comprise: a first reference pointcorresponding to an intersection of a posterior fontanelle and aperpendicular plate of a palatine bone; a second reference pointcorresponding to the sphenopalatine foramen; and a third reference pointcorresponding to a ridge of an inferior turbinate.
 8. The method ofclaim 7, wherein the ablation end effector comprises a planar member,wherein the one or more location sensors comprise three location sensorspositioned on the planar member, and wherein determining that theablation end effector is aligned with the target treatment locationcomprises determining that each of the three location sensors arepositioned at one of the first reference point, the second referencepoint, and the third reference point.
 9. The method of claim 8, whereindetermining the ablation end effector is located at the target treatmentlocation comprises using an indication of the position of each of thethree location sensors relative to the first reference point, the secondreference point, and the third reference point of the target treatmentlocation displayed on a display.
 10. The method of claim 7, wherein theone or more location sensors comprise at least three location sensorsdisposed on or within an expandable structure of the ablation endeffector coupled to a distal end of the surgical probe, and whereinperforming ablation of the tissue region comprises introducing acryogenic fluid into the expandable structure such that the expandablestructure inflates from a deflated configuration into an expandedconfiguration against the surface of the target treatment location. 11.A system for treating a tissue region within a nasal cavity, comprising:a surgical navigation device; and a surgical probe comprising anablation end effector and one or more location sensors that aredetectable by the surgical navigation device, wherein the surgicalnavigation device is configured to: identify a target treatment locationof the tissue region on an image of the nasal cavity, and register theablation end effector of the surgical probe in the nasal cavity with theimage of the nasal cavity to the nasal cavity to establish a referenceframe, determine a position of the one or more location sensors disposedon the surgical probe with respect to the reference frame, and determinewhen the ablation end effector of the surgical probe in the nasal cavityis aligned with the target treatment location prior to ablation of thetissue region, and wherein the ablation end effector is configured to beinsertable into the nasal cavity and positioned at the target treatmentlocation using the position of the one or more location sensors in thereference frame, and configured to ablate the target treatment locationwhen the ablation end effector is determined to be at the targettreatment location.
 12. The system of claim 11, wherein the referenceframe is established based on one or more anatomical features of apatient or location sensors disposed on the patient.
 13. The system ofclaim 11, wherein the surgical navigation device is configured toidentify the target treatment location by identifying a sphenopalatineforamen in the image of the nasal cavity.
 14. The system of claim 13,wherein the target treatment location is determined by measuring apredetermined distance or a predetermined direction from thesphenopalatine foramen in the reference frame.
 15. The system of claim13, wherein the target treatment location is a surface in the nasalcavity and the surface is defined by a plurality of anatomical referencepoints.
 16. The system of claim 15, wherein the anatomical referencepoints comprise: a first reference point corresponding to anintersection of a posterior fontanelle and a perpendicular plate of apalatine bone; a second reference point corresponding to thesphenopalatine foramen; and a third reference point corresponding to aridge of an inferior turbinate.
 17. The system of claim 16, wherein theablation end effector comprises a planar member and the one or morelocation sensors comprise at least three location sensors disposed onthe planar member, and wherein the surgical navigation device isconfigured to determine that the ablation end effector is aligned withthe target treatment location by determining that one or each of the atleast three location sensors are aligned at one of the first referencepoint, the second reference point, and the third reference point. 18.The system of claim 17, wherein the surgical navigation device isfurther configured to generate an indication of the position of each ofthe at least three location sensors relative to the first referencepoint, the second reference point and the third reference point of thetarget treatment location on a display.
 19. The system of claim 16,wherein the one or more location sensors comprise at least threelocation sensors disposed on or within an expandable structure of theablation end effector coupled to a distal end of the surgical probe, andwherein the ablation end effector is configured to introduce a cryogenicfluid into the expandable structure such that the expandable structureinflates from a deflated configuration into an expanded configurationagainst the surface of the target treatment location.
 20. The system ofclaim 11, wherein the image of the nasal cavity is based on a computedtomography scan or a magnetic resonance imaging scan.
 21. The system ofclaim 20, wherein the target treatment location is a surface in thenasal cavity and the surface is defined by a first reference pointcorresponding to an intersection of a posterior fontanelle and aperpendicular plate of a palatine bone, a second reference pointcorresponding to the sphenopalatine foramen, and a third reference pointcorresponding to a ridge of an inferior turbinate, wherein the ablationend effector comprises a planar member and the one or more locationsensors comprise three location sensors disposed on the planar member,and wherein determining that the ablation end effector is located at thetarget treatment location comprises determining that each of the threelocation sensors are aligned one of the first, second and thirdreference points.
 22. The system of claim 21, wherein the surgicalnavigation device comprises a display configured to provide anindication of the position of each of the three location sensorsrelative to the first reference point, the second reference point, andthe third reference pint of the target treatment location.
 23. Thesystem of claim 20, wherein the target treatment location is a surfacein the nasal cavity and the surface is defined by a first referencepoint corresponding to an intersection of a posterior fontanelle and aperpendicular plate of a palatine bone, a second reference pointcorresponding to the sphenopalatine foramen, and a third reference pointcorresponding to a ridge of an inferior turbinate, wherein the one ormore location sensors comprise three location sensors located on orwithin an expandable structure of the ablation end effector coupled to adistal end of the surgical probe; and wherein performing ablation of thetissue region comprises introducing a cryogenic fluid into theexpandable structure such that the expandable structure inflates from adeflated configuration into an expanded configuration against thesurface of the target treatment location.